Suitable For Harnessing Solar Energy Engineering Essay

 


There are several projects like photovoltaic cell in solar panels, solar power concentrator and parabolic dishes devised to harness solar energy in India. These plans prove very fruitful in south eastern parts of India in Tamil Nadu, Karnataka, northern plains in Uttar Pradesh, Bihar, western part of India in Rajasthan and parts of Gujarat. In short, those places which have annual average temperature of more than 25°C are suitable for utilizing this energy into usable power.


In this project we have tried to put up a new way of converting electrical energy directly into mechanical energy without any use of solar cell or mirrors. The idea is supposed to be simple as there is no involvement of dedicated machinery or setup and practically no running cost.


The basic idea lies in the structure and way of using solar energy. In this project, the aim is to convert solar energy into kinetic energy of wind and then use this wind for purposes like rotation of turbine or for any other mechanical work. The basic principle involved is that the heated air is lighter than the cold air. If air gets heated near the surface of earth, then it tries to move up into atmosphere and replace the position of cold air from surrounding. The heated air which moves up, acquires a kinetic energy while moving and can be used to rotate the blades of turbines, if stroked with pressure.


The structure consists of a metallic dish made up of aluminium in which the distance between two diametrically opposite points is 20 meters which has a hole in its centre and is placed on supports such that its outer boundary lies at a distance of 3 meters from ground level. Eight rods made of iron are used as a support, which are inserted in the ground. A frustum shaped pipe with a nozzle at the upper end and lower diameter of 1 meter is used to impart the hot air up to the blades of turbine and a iron pipe of lower diameter 1 meter and length of about 10-15 meters is used to hold this nozzle and turbine. The dish must be designed in such a way that its centre lies 1 meters high from its outer boundary, that is, it forms the shape of a big umbrella roof as shown in figure.


WORKING:


This structure helps us to direct all heated wind toward the centre of the dish and no air is escaped from the outer boundary of dish. The heated air when passed through the centre of dish, tries to move through the thin pipe which further has a nozzle at the end. So the escaping wind moves like a high speed stream in that pipe just like steam as it passes in the thermal power plant, strikes the blade of the turbine which is just in front of nozzle and transfers its momentum and ultimately the blade moves and the next blade comes in place of previous one. Due to the continuous flow of hot air, the turbine starts rotating and hence the connected shaft also starts delivering mechanical output. The cold air moves inside from the bottom of dish and take the place of hot air, gets heated and moves up and thus the cycle continues, and we get mechanical power in the form of rotating shaft of turbine which can be used either to generate electricity, which is our main requirement or in other forms as well, where we need mechanical power, like in pumps or other mechanical machines.


The main difference in this solar power set up and other plants utilizing the same energy is that here we get mechanical energy as the outcome and we can use it in numerous ways but in other projects, like in solar panels and rotating dish we get electrical energy only, this is quite an advantageous part of this project. The other advantage of this project is that we can use the hot air produced through this installation for various other plants and industrial applications like, in drying operation in chemical industries, heat exchangers and preheating of water in thermal power plants and at domestic level it can be used for room heating, driers and water heating which will greatly reduce the domestic power consumption as power consumption in water heating accounts for about 30% of electricity bill and thus this heated gas helps to minimize the electric consumption.


The problem lies in the efficiency of the turbine used, that is, nowadays the turbines manufactured are good for higher speed stream wind but in our model we need a better and lighter turbine which rotates with greater r.p.m with the given speed of wind. As the power output and mechanical work, both depend upon the r.p.m of the rotating shaft so it should be high and for increasing the r.p.m there must be an improvement in our present technology, in the sector of turbine design and material science for improving the quality of materials used for turbine design. The existing industry products require a minimum wind speed of 25 km/hr for production of 10 MW of power, thus we have to improve our technology to reduce this speed.


The other possible disadvantage of this project which is common for most of the solar plants is that, it will not work at night or in rainy seasons. As there will be lesser chances of availability of sun in those periods, hence less heated air production and consequently reduction in movement of air, so power production would get a pause for this period. The idea of storage of energy in rechargeable batteries might prove useful for those periods. There must be regular supervision and checking of the dish to prevent the development of holes and cracks in it, as it would greatly reduce the efficiency of the system by leaking the air. The overall performance would also be greatly affected.


COST, INVESTMENT AND RETURN:


Surface Area of Dish can be calculated as:


(X + 1)2 = 102 + X2


(X2 + 1 +2.X) = 100 + X2


2X = 99


X = 49.5 m


Hence, Radius = 50.5 m


Sin? = (10/50.5)


? = Sin-1(10/50.5)


? = 11.42o


Hence, the ends of the dish make an angle of (2 x 11.42) = 22.84o


Therefore, the Surface area of dish = (?/360) x 4p x (Radius)2


= (22.84/360) x 4 x (22/7) x (50.5)2


= 2034 m2


Since, Thickness of dish =3mm


Therefore, Volume of dish =2034 X.003=6.102 m3


Surface area of circular pipe = p X Diameter of pipe X Height of pipe


=3.14 X 1 X 10m


=31.4 m2


Thickness of Pipe = .005 m


Volume of material used in pipe= 31.4 X .005=0.157 m3


The cost analysis is done by discrete method, that is, by quantizing various costs as follows:


a) Cost of dish= (area of dish) X (thickness of plate) X (Density of metal) X cost of metal per kilogram = 2034m2 X .003 m X 2700kg/m3 X Rs130/kg = Rs 2142000


b) Cost of eight supports= 8 X 3 m X cost per meter of support= 24 X 3 m X Rs 150/m =Rs 10800


c) Cost of pipe= (curved surface area of pipe) X cost of sheet = 31.4 m2 X Rs 200/m2 = Rs 6280


d) Cost of nozzle and frustum = Rs 10000


e) Cost of turbine, blades and shaft= Rs 0.5 million


f) Labour charge= Rs 3 million


g) Maintenance cost and land rent= Rs 1 million


h) Miscellaneous charge= Rs 2-2.5 million rupees


TOTAL expected cost = Rs8.6 million


RETURN ANALYSIS:


In Indian scenario we have almost 300 clear sunny days and on an average 10 hours of bright sunlight available so we can calculate the power output in kilowatt hour as


300 X 10 X 60 X 60 X 10 MW/3.6 X 106


=3 x107 KWh of power


Expected sales rate = Rs 2 per unit


Total expected annual return = Rs 60 million


Expected annual profit: Rs 51 million


After analysing the cost and return, it is found that this project remains profitable over the year and gives a profitable return in the summer season.


EFFECT OF GOVERNMENT INCENTIVES:


The Government of India has a very positive and supportive approach towards the solar power. It provides manufacturers and users of commercial and near commercial technologies, with ‘soft’ loans on favourable terms through the IREDA (Indian Renewable Energy Development Agency). The RBI (Reserve Bank of India) terms the renewable energy industry as “Priority Sector”, and has permitted Indian Companies to accept investment under the ‘automatic route’ without obtaining prior approval from RBI.


The Govt of India also provides exemptions/concessions in the excise tax duty on the manufacture of the solar energy systems and devices such as flat plate solar collectors, solar water heater and systems and any specially designed devices which operate those systems. Their incentives include concession on custom duty, 10 year tax holidays and sales and electricity tax exemption and preferential tariffs. It also includes capital subsidies.


The financial assistance of the Central Government is one of the factors which are highly helpful in the solar power market. It provides up to Rs 50 lakhs per city for a period of 5 years, Rs 20 lakhs for awareness generation, capacity building and other promotional activities, Rs 10 lakhs for preparation of a master plan, setting up institutional arrangements, oversight of implementation during the period of 5 years respectively.


The State Electricity Regulatory Commission has been mandated to source up to 10% of their power from renewable energy sources.


The Government based incentives also provide INR 0.5/ KWh of power sold, for independent power producers with capacity >5MW, for the projects that don’t claim accelerated depreciation benefits.


The State Government has set a remunerative price under power purchase policy for the power generated through solar energy system, fed to the grid by private sector. It also has provisions and policy packages including banking, third party sale and buy-back of solar energy power. The State Government also encourages NGO’s and small entrepreneurs for their participation in solar power market.


In a nutshell, the Indian government provides its support to a larger extent for the development of a sustainable solar power market.


SOLAR POWER MARKET:


India has seen only modest pace of growth , relative to demand , in solar power generation. This has resulted in persistent supply shortages for both urban and rural customers. The main customers of solar power generation market include homeowners, businesses and utility companies.


The demand for electricity in developing countries is growing at a fast pace. The potential worldwide market for solar power over the next 20 years is estimated at 600 GW or 6000 plants of 100 MW solar capacities, most of this in developing countries like India.


Over the next 20 years, It is predicted that there will be actual installations of 45 GW or over twenty 100 MW solar capacity plants per year, assuming niche markets could allow for a 7.5% penetration rate. The actual penetration rate will depend on progress in reducing the cost/performance ratio, support from governments (and the GEF), and energy prices.


The above graph represents the daily utility load profiles for four developing countries: India, Jordan, Egypt and Mexico. The values for India are the average of three regions. After analyzing the above graph, one can forecast that the solar power has a great future in developing countries; hence this plan can be promising for India as it has its maximum consumption in day time so we can rely on this type of setups for our energy needs.


In 2008, the cumulative Solar power capacity was 15 GW. Growth in recent years has been 15% per year. There are estimated 40 million households (2.5% of the total) which were using solar power worldwide in 2004.


China is the leader; 10% of Chinese households use solar power; the target for 2020 being 30%.


In 2008, 65.6% of existing global solar power capacity was in China; followed by European Union (12.3%), Turkey (5.8%), Japan (4.1%) and Israel (2.8%). The Indian share was 1.2%.


The estimated break up of solar power installations in India (till 2009) is as follows:


Residential (80%)


2.108


Hotels (6%)


0.158


Hospitals (3%)


0.079


Industry (6%)


0.158


Other (Railway + Defence + Hostel + Religious places,


other) (5%)


0.132


2.635


The main factors contributing the demand rise in recent years are


• Growth in new urban housing; rising disposable income; increased propensity for consumer durables


• Arrival of ETC & improvements in supply chain


• Energy price hike


• Policy initiatives


According to a survey, five states will lead demand-expansion, as is evident from the following table:


Karnataka


3.72


0.16


3.88


Maharashtra


3.5


0.31


3.80


Tamil Nadu


1.53


0.14


1.67


Andhra Pradesh


1.08


0.09


1.17


Gujarat


0.9


0.06


0.96


%age of 5 states


67.1%


Analysis of demand at the district level shows that a large part of the demand would come from selected urbanized districts. Some of the key districts (out of the 29 surveyed districts) which have large potential for solar power generation market are Bangalore, Pune, NCR, Thane, Hydrabad, Nagpur, Kolkata, Chennai, Coimbatore, Ahmadabad and Jaipur. Among them, Bangalore has highest solar power potential of about 1.94 million m2, in 2022.


Solar power market development plan:


The solar power market development plan is divided into 3 phases:


1. Niche Market Awareness:


The main objectives are to rekindle interest in Solar power generation in India, allow the industry to start-up production processes, determine the current cost and performance of Solar power generation ,and evaluate new Solar power generation concepts to see if they have promise for long term commercialization.


The main activity is to increase market awareness by funding one or two Solar plants in


India. These plants will likely be smaller than the optimum of over 200 MW because of the need to minimize investor risk and to start-up production processes.


It is recommended that the initial market focus should be in those markets where the conditions for solar power generation are currently most promising. Previous experience shows that these conditions are High Solar Resource, High fossil fuel prices, Daytime Peaking Utility, Inefficient Conventional Power Plants, Access to Water and the Grid.


Depending on the cost of power displaced, the financial support to achieve cost parity will range from $400 to $750 million or $550 to $1000 per kW.


2. Market Expansion:


The purpose of the market expansion phase is to develop larger systems to benefit from economies of scale, continue with product development to improve performance and lower costs, create a market large enough that manufacturers can justify construction of production lines, and standardize system designs. A standard design will help to improve the system cost performance by reducing design costs, streamlining equipment procurement and minimizing construction and start-up problems.


In this phase, 3000 MW of additional solar capacity is installed, or fifteen 200 MW plants. The cost of solar power is expected to fall from over 10 cents/kWh to between 7 and 8 cents per kWh.


Depending on the cost of power displaced, the financial support to achieve cost parity will range from $0.5 to $1.8 billion or $350 to $600 per kW.


3. Market acceptance:


The final part in the development plan is the market acceptance phase. The goal for this phase is to set up the necessary market structure so that solar power generating plants can compete with conventional power plants without financial support from the GEF or others.


The investment requirement in this phase is the most difficult to estimate and subject to the


widest variation. The cost of solar generated electricity is expected to fall close to conventional power values. A small difference in solar costs can have a huge impact on the market penetration.


Solar power generation market has the ability to dramatically transform lives. In a country, where 450 million people live without access to electricity and have to depend on kerosene and other alternatives for whatever little lighting they can get at night, solar power as an application in small home lightening system lightens up their lives.



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